And the question is? Use a Coast 1B-1X fill valve, (you may have to push its "rim flush" hose inside the Pomptom's existing one to get a good seal. Than just screw a new tank ball, maybe a 3" one, on the lift wire.

Cool! But for what it must have cost for Kohler parts and your time, they would doubtless have been able to buy a Soiree.

I'm guessing that they wanted to keep the brown Pompton because they have a brown sink and a brown tub. Or you couldn't sell them on the idea that one didn't need 9.5 gallons to flush a toilet reliably.